Facebook is a brilliant social-networking platform with billions of users who join (one assumes) to make “friends” — not enemies. But Facebook CEO Mark Zuckerberg has decided it’s also a welcome hangout for Holocaust deniers. Explaining why it’s his policy to not remove the anti-Semitic content of deniers, Zuckerberg advised that “there’s a set of people who deny that the Holocaust happened … I don’t believe that our platform should take that down because I think there are things that different people get wrong.”

Wrong content is one thing. Holocaust denial is not just “wrong,” it is hate speech. Just as Facebook does not allow posts that espouse violence, it should not allow users to defend the most horrific genocide in our history: the Holocaust. Not surprisingly, Zuckerberg’s comments have sparked a public outcry.

Holocaust denial is pure anti-Semitism. Throughout history we have learned that anti-Semitism is in fact lethal and Auschwitz stands, with so many other death camps, as a stark and unforgettable testament to that. The Holocaust was a consequence of anti-Semitism. So were the countless violent pogroms that preceded the Holocaust, when hateful people spreading lies and libels saw to it that Jews were marginalized, dehumanized and murdered.

Jews have suffered throughout history because of those who deny the truth and peddle falsehoods about us. Anti-Semitic propaganda tracts such as The Protocols of the Elders of Zion and The International Jew have for generations spread lies and hate against Jews. The blood libel — the lie that Jews are murdering Christian children to use their blood in rituals — was once spread by word of mouth from village to village to incite people to harm Jews. Today’s lies are spread on social media sites, especially Facebook.

To compare conspiracy theories with people who are simply “wrong” completely misunderstands the motives behind these denials. Those who promote Holocaust denial reveal their anti-Semitism in their enthusiasm for targeting and belittling the most painful episode in modern Jewish history and portraying it instead as a hoax perpetrated by those same powerful and nefarious Jewish caricatures that have always been a staple of anti-Semitic propaganda. Theirs is an intentional act of conspiracy-mongering, to incite hatred against another group. That is why Holocaust denial is now illegal in many of the countries where it was perpetrated. In Germany, Austria, France, Italy, Hungary and Romania, they know what terrible things can come when lies are allowed to spread about Jews.

Zuckerberg says he believes Holocaust deniers were not “intentionally” getting their facts wrong. So, he means someone overlooking all the evidence we now have about the Holocaust, the most well-documented genocide ever committed — the Nazis own records, the minutes of the Wannsee Conference where the Final Solution was hatched, the words of all the survivors and living witnesses who saw the camps first hand, including former Nazi guards, and of course the physical evidence of the camps and murder sites — is making an innocent mistake. They’re operating in good faith. These things just happen, do they?

No. And Zuckerberg, as a Jew himself, should know better. He has since tried undoing the damage of his initial comments, clarifying later that “I personally find Holocaust denial deeply offensive, and I absolutely didn’t intend to defend the intent of people who deny that.” That’s too little, too late. What Zuckerberg has yet to say is that he will rethink his attitude about the Holocaust and work to stop hateful deniers from spreading libels and lies against a long-persecuted people. Have we learned nothing?